Separately-fired superheater



June 19, 1928. Y 1,674,424

Y B. N. BROlDO SEPARATELY FIRED SUPERHEATER Filed June 9, 1924 4 Sheets-Sheet 1.

3 TlIq-l- 4 INVENTOR BENJA IN lV. 5/20/00 MJZAWa ATTORNEYS June 19, 1928 1,674,424

B. N. BROIDO SEPARATELY FIRED SUPERHEATER Filed June 9, 1924 4 Sheets-Sheet,

INVENTOR BEAN/4171M N. 5/?0/00 ATTORNEY June 19, 1928. 1,674,424,

B. N. BROIDO I SEPARATELY FIRED SUPERHEATER Filed June 9, 1924 4 Sheets-Shea; 5

INVENTOR BE/vdflM/N BRO/D0 ATTORNEY June 19, 1928.

B. N. BROIDO SEPARATELY FIRED SUPERHEATER Filed June 1924 4 Sheets-Sheet 4 INVENTOR 3m MI 7 d Patented June 19, 1928.

UNITED STATES BENJAMIN N. BROIDO, OF NE! YORK N. 'Y.. ASSIGNOR TO THE SUPERHEATER COIL PATENT orrfics.

PAN'Y, OF NEW YORK, N. Y.. A CORBORATION OF DELAWARE.

SEPARATELY-FIRED SUPER-HEATER.

Application filed June 9, 1924. Serial No. 718.695.

This invention relates to super-heaters and a-rticularly to separately fired superheatcrs as distinguished from that type of superbcatersconstructed as a part of, or installed in, an ordinary steam boiler.

It is .the principal object of this invention to provide a new and improved construction of a separatelyfirgd superheater which will I be of such high thermal efliciency as to make the use thereof practical from'a'n economical standpoint. Another object is to combine with such a superheatcr, means for heating .the feed water supplied to the boiler; a part of such means being constructed and arrangedto act as a protective screen for those portions-of the superheater which are subjected to the greatest heat.

These and other more specific objects will appear from the following description and by reference to the accompanyingdrawings, which illustrate-an example. of my invention without defining its limits, .artdwvherein, Fig. 1 is a longitudinal vertical section taken substantially on the line 1-1 of F ig. 2.; Fig. 2 is a plan view and Figs. 3 and 4 are sections on the lines 3'3 and 4-4 respectively of Fig. 1.

As thespecific details of the furnace or fire box portion of the apparatus form no part of the present invention, only a small portion thereof has been shown in the drawings in order to permit the construction and mounting of the superheater units to be shown on a larger scale. A fire wall 11 which extends across between the side walls 12 and-13 serves to divide the furnace or.

fire box chamber 10 from the'superheater chamber 14 and terminates at a point approximately half way between the top and bottom of the structure to provide an inlet for the furnace gases to the chamber 14. A wall 15 extends longitudinally along the central part of the chamber 14 and a plurality of transversely extending bafile walls 16. 17 and 1.8 are provided within said chamber to define a tortuous passage for the products of combustion from the furnace through the superheater chamber. The walls 16 and 13 terminate short of the floor of the chamber to provide the passages 19 and 20 and the wall 17 terminates short of the top wall thereof to provide a passage 21. It will be noted that the passages defined by the baflle walls decrease in horizontal cross-sectional area from the froiit towards the rear of the apparatus to offset the shrinkage due to the cooling of the gases,

An inlet manifold 22. which extends. par- 16.and 18. An outlet manifold30, located adjacent to the side wall 13, is provided with the lateral branches3l and 32 to which the outl'st headers 33 and 34 areconnected.

A plurality ofrows of superheater tubes or units are mounted Within the superheater chamber and are suitably connected to the inlet and outlet headers. Each superheater unit consists of a plurality of lengths of tubing. connected at their adjacept top and bottom ends by a return-bend 40 preferably united to the tubing by a special forging operation which forms each unit into an integral structure of great strength and durability. As the first loops 35 0f the units 35 of the first row are exposed to the hottest gases, the units 35 are made into two separable sections 35 and 35. connected by a double ball coupling joint 35 so as to permit the replacement of the first loop without necessitating the replacement of the second loop. preferably arranged in staggered relation as shown in Fig. 1, while the loops of theremainin; rows are arranged in alignment transversely of the apparatus. The units 35 are connected at their front and rear ends respectively to the inlet header 26 and outlet header 33; the units 36 of the second row to the inlet header 27 and outlet header 33; the units 37 of the third row to the inlet header 27 and the outlet header 34; and the units 38 of the last row to the inlet header 28 and the outlet header 34. Spacing plates 42. and 43 are provided at suitable points to hold the units in proper position.

The units 35 which form the first steam pass are preferably of heavier tubing than the other units to withstand the higher temperatures to which they are subjected, and said units 35 are also of shorter overall length than the other units to decrease the The loops 35 of the first units are area of the gas passage and thereby assists in increasing the velocity of the gases in this passage, V A water screen, which consists of a plufrality of pipes 46, 46 preferably arranged ,in two closely spacedvertieal rows withthe pipes of each row staggered relatively to fthoseof the adj acent'row, extends across th ispac'eabove thefjfi're, wall 11; one end of said pipes being, connected tothe vertically ex- ;tending inlet header'flfl and the other end of saidlpipes, being connected to the outlet I header 48., It willbe noted by referring to Fig, -3 ftl rat[ the pipes 46, 46* are inclined upwardly from the inlet header 47 towards the outlet header 48 to permit the escape of any bubbles which might be'formed within said pipes; It will also be noted that the spaces between adjacent'pipe's 46, 46, in-

crease gradually from the bottom towards the top of the water screen, thereby providing a freer passage for the gases towards the top. and a; relativelyfrestricted passage towards the bottom. This arrangement insures a better distribution of the gases over the entire water screen and over the first row of superheater units, and also serves to afford better protetction of those parts of the units located nearestto the fire bed.

An eco1'1omi'zer49 of any suitable construction, placed within the last or outlet pass 50 01: the superheating chamber, serves to give a preliminary heating 'to the feed water for the boiler. The water enters the economizer at the top thereof, through the supply header 51, and flows through the economizer in counter-flow with respect to the gases,

that is to say from the top vto the bottom thereof. The .feed water then passes from the economizer throughth'e outlet header 52 which is connected by the pipe 53 with the vertical inlet header 47 of the water screen. While the arrangement described by connecting the water screen and the eeonomizer may be resorted to in many installations, it will be obvious that it is within the spirit of my invention, in cases where it may be found desirable to supply water for two different purposes, as for example, feed water, and water for process or other uses, the water screen and economizer will not be connected. In such cases, therefore, separate supply and outlet pipes for the water heating memberswill be employed.

It will be noted that saturated steam is introduced into both the first and last passes of the superheater, the steam flowing counter to the gases in the last units 38 so that the last heat is taken from the gases by the coolest steam and to secure the most eflicient heat exchange by counter flow in accordance with the well known laws of thermo-dynainics.

In the first units 35 the steam flow is parallel to the gas flow so as to furnish better protection to the loops 35 nearest the fire, the coolest steam passing through these loops rst.

The provison of the water screen ahead of the superheater units .serves to protect the superheater units as itacts as a'heat absorbing surface to cool the gases before they contact with the superheater units and also performs the function of acheckered wali, breaking up the flame and preventing it from impinging directly on the super heater units 35; As the water screen contains 'water while the superheater units contain steam, the temperature of the pipes-46 will be less than the loops 35", therefore there will be a heat exchange between the'loops 35 and the pipes 46 of the water screen, which will also tend to prevent burning out of these loops.

/ The construction of the inlet"and outlet manifolds, the headers connected thereto and the manner in which thejsuperheater units are connected to the headers provide an assembly which'is very elastic,that is to say, one in which the capacity of the ap paratus may not only be readily increased or decreased as desired, but which also permits the replacement of anyunits, to be easily and quickly accomplished.

While I haveshown the water screen as constructed of two' rows of pipes 46,both rows being connected to a. common header On each side of the apparatus, it will be obvious that two or more'headers'may be supplied on each side, and also that in addition to using the water or other fluid from the water screen and economizer for two different purposes, the fluid heated in the water screen may also be employed for different purposes by resorting to the expedient of using" separate, unconnected headers for any number of the pipes 46. Instead of using two rows of pipes 46 it will also be obvious that only one row or that any number of rows of pipes may be subin each row, the location of the headers and the use of manifolds will be varied accordingto the requirements of the plant, and that'otherchanges, variations and modifications of the constructional details may be I adopted without departing from the spirit of my invention.

' 1 I claim 1: In a separately fired superheater, a furnace, a superheatmg chamber having an inletcommunicating with said furnace and an outlet, said chamber being provided with a-;pluralityof baffle Walls arranged to provi' e for thefurnaee' gases: a tortuous pass'aidzisuperheating :chamber and, forming a 'plhrailityof separate steam passes arranged m parallel, each' of said separate steam passes being contained entirely within a rsepa-rate gas pass, and means to supply the steam to be superheated to said plurality of separate passes. I a

2. In a separately tired superheater, a furnace, a superheating chamber having an inlet communicating with said furnace and an outlet, said chamber being provided with a plurality of baffle walls arranged to provide a tortuous passage for the furnace gases, said passage decreasing in cross sectional area from said inlet towards said outlet, a plurality of groups of superhcater units mounte within said tortuous passage at different distances from said furnace and arranged to provide a plurality of separate steam passes connected in parallel and means to supply the steam to be superheated to said plurality of separate passes.

3. In a superheater, a furnace, a plurality of groups of superheater units arranged to form a first pass located closest to the furnace, a last pass located farthest from the furnace and a plurality of intermediate passes, and means to cause the steam to flow in parallel through said passes, in uniflow and counterflow with the furnace gases through said first and last passes respectively.

4. In a separately fired superheater, a furnace, a superheating chamber having an inlet communicating with said furnace and an outlet, a plurality of separate groups of superheater units mounted within said chamher through which the steam to be superheated is conducted in separate passes. one of said groups of superheater units being located adjacent to said inlet and another of said groups being located adjacent to said outlet. and means to supply saturated steam to each of said last named groups of units in separate iasses in parallel relationship, in uniflow with the furnace gases in the first 'named group and in counterflow with the furnace gases in the last named superheater units. a

5. In a superheater, a furnace, a plurality of groups of isuperheater units arranged to form a plurality of separate parallel steam passes locatedat different distances from said furnace, and means to cause the steam to flowthrough the first of said steam passes nearest to the furnace in unifiow with the furnace gases and in't-hepass farthest from said furnace in counterflow to the furnace gase's,.said first pass beingof such shorter length than the last pass that substantially group of the same degree of superheatiis imparted tothe steam in each of said passes.

6. In a separately fired superheater,a furnace, a .superheating chamber having an inlet communicating with said .furnace through which-the furnace gases flow-,a plnralityofi superheater units mounted within said chamher and arrangedinspaced-rows at different distancesafrom said furnace, an inlet manifold and an outlet manifold, and connections therefrom to said superheater units tocause the steam to pass in separate parallel steam passes through said spaced rows, the first row of units immediately adjacent to said furnace being of shorter overall length than the units of the remaining rows whereby the steam flow through said first row of units will be at a greater velocity than the flow through said remaining rows.

7. In a separately fired superheater, a furnace, a superheatin chamber having an inlet communicating wit 1 said furnace, said chamber being provided with a plurality of baflie walls to provide a tortuous passage of decreasing cross sectional area for the furnace gases through said chamber, a plurality of superheater units arranged in spaced parallel rows at different distances from said furnace and projectingiuto said chamber between said walls, an inlet manifold, an outlet manifold and connections from said manifolds to said units to cause the steam to be passed in parallel through said units in a plurality of separate steam passes.

8. In a separately fired superheater, a furnace, a superheating chamber having an inlet communicating with said furnace, said chamber being provided with a plurality of baflle walls to provide a tortuous passage of decreasing cross sectional area for the furnace gases through said chamber, a plurality of superheater units arranged in spaced rows at different distances from said furnace, and projecting into said chamber between said walls, an inlet manifold. an outlet manifold and connections from said manifolds to said units to cause the steam to be passed through said units in a plurality of separate parallel steam passes, and a plurality of baffles arranged in said chamber and extending across the last rows of superheater units to reduce the effective cross sectional area of, and thereby increase the velocity of the gases in that part of the gas passage in which said last rows are located.

9. In a separately fired superheater, a furnace, a superheating chamber having an inlet communicating with said furnace, said chamber being provided with a plurality of bafiie walls to provide a tortuous passage of decreasing cross sectional area for the furnace gases through said chamber, a plurality of superheater units arranged in spaced rows at different distances from saidfurnace and projecting into said chamber between said walls, an inlet manifold, an outlet manifold and connections from said manifolds to said units to cause the steam to be passed in parallel through said units'in a plurality of separate steam passes, the steam passes adjacent to said furnace being of shorter overall length than the remaining passes to cause the steam to flow therethrough at a greater velocity than through the remaining passes.

10. In .a separately fired superheater, a furnace, a superheating chamber having an inlet communicating with said furnace, said chamber being provided with a plurality of baffle walls to provide a tortuous passage of decreasing cross sectional area for the furnace gases through said chamber, a plurality of superheater units arranged in spaced rows at different distances from said furnace and projecting into said chamber between said walls, an inlet manifold, an outlet manifold and connections from said manifolds to said units to cause the steam to be passed in parallel through said units in a plurality of separate steam passes, and a plurality of baflles arranged in said chamber and extending across the last rows of superheater units to reduce the efi'ective area of, and increase the velocity of the gases in, that part of the gas passage adjacent to said last rows, the rows of units adjacent to said furnace being of shorter overall length than the remaining rows to cause the steam to flow therethrough at a greater velocity than through the remaining rows.

In testimony whereof I have hereunto set my hand.

BENJAMIN N. BROIDO. 

